1. Field of the Invention
The present invention relates to a solid-state image sensor and a camera.
2. Description of the Related Art
A living body has transmittance of infrared light having a wavelength of 800 to 1,000 nm. A technique of visualizing the interior of the body by injecting, into the body, a drug which is excited by infrared light to emit fluorescence in the infrared range, and detecting the fluorescence is attracting attention. A monochrome image sensor sensitive to the infrared range can capture fluorescence in the infrared range from the inside of the body. In addition, it is required to simultaneously output color information, and to monitor a visible light image and an infrared light image at the same time. A method of performing imaging using a visible light image sensor and an infrared light image sensor, and superimposing the thus obtained images on each other is plausible. However, it is difficult to reduce the size and cost. It is, therefore, required to obtain a visible light image and an infrared light image using a single image sensor.
Japanese Patent Laid-Open No. 2010-35168 discloses an imaging device which alternately outputs a color frame formed by red, green, and blue pixels and a depth frame obtained by detecting infrared rays in these pixels.
The imaging device described in Japanese Patent Laid-Open No. 2010-35168 can increase the sensitivity to infrared rays since it detects infrared rays in four pixels to obtain one signal. In the imaging device described in Japanese Patent Laid-Open No. 2010-35168, the four pixels are also pixels for obtaining red, green, and blue signals, and thus visible light noise is mixed into an infrared signal.